Unix & Linux Stack Exchange is a question and answer site for users of Linux, FreeBSD and other Un*x-like operating systems. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I am attempting to run GPU computation software on Ubuntu Server 12.04 without X since this box is going to be a dedicated computation machine. However the last requirement "Without X" is proving to be very problematic.

I have a ATI Radeon HD 5770 hooked up right now. Installed the x64 drivers from AMD's website by having it generate the correct debian packages. Ran sudo aticonfig --initial --adapter=all and rebooted. However it doesn't seem like its working

adam@adamcrunch:~$ DISPLAY=:0 fglrxinfo
Error: unable to open display (null)
adam@adamcrunch:~$ sudo aticonfig --list-adapter
* 0. 01:00.0 ATI Radeon HD 5700 Series

* - Default adapter

My software is also having issues as it just won't use the GPU for computation and tries to use the CPU.

I know during my initial install with Xubuntu that the card works and I can do GPU computation on it. However is it possible to do it on a headless server without X?

I can provide more information if needed

share|improve this question
Take a look at Xvfb or something similar. – nsg Oct 4 '12 at 13:51
may be env DISPLAY=:0 fglrxinfo? – Serge Oct 4 '12 at 15:16
@Serge Tried that as normal user and root, same result – TheLQ Oct 4 '12 at 15:37
@nsg I didn't know such things existed. I will give xvfb a try then – TheLQ Oct 4 '12 at 15:38
@TheLQ Xvfb wouldn't help: that's an X server backed by memory. You need an X server that talks to the video card. There's no reason not to run an X server, even if you don't have a monitor plugged in. – Gilles Oct 4 '12 at 21:46

AMD's implementation of OpenCL requires that:

  1. An X server be running on at least one of the AMD video cards in the system.
  2. Your compute jobs must run within that X server.

If this is something you can't possibly do, then you should consider using different hardware, such as NVIDIA.

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.